NAME

tcflow −  Performs flow control functions

LIBRARY

Standard C Library (libc.a)

SYNOPSIS

#include <termios.h>

int tcflow(
int filedes,
int action );

PARAMETERS

filedes Specifies an open file descriptor. 

action Specifies one of the following:

TCOOFF
Suspend output.

TCOON
Restart suspended output.

TCIOFF
Transmit a STOP character, which is intended to cause the terminal device to stop transmitting data to the system.

TCION
Transmit a START character, which is intended to cause the terminal device to start transmitting data to the system.

DESCRIPTION

The tcflow() function suspends transmission or reception of data on the object referred to by the filedes parameter, depending on the value of the action parameter. 

A process group is sent a SIGTTOU signal if the tcflow() function is called from one of its member processes.  If the calling process is blocking or ignoring SIGTTOU signals, the process is allowed to perform the operation and no signal is sent. 

NOTES

AES Support Level: Full use

RETURN VALUES

Upon successful completion, a value of 0 (zero) is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error. 

ERRORS

If the tcflow() function fails, errno may be set to one of the following values:

[EBADF] The filedes parameter does not specify a valid file descriptor. 

[EINVAL] The action parameter is not a supported value. 

[ENOTTY] The file associated with the filedes parameter is not a terminal. 

RELATED INFORMATION

Functions: tcdrain(3), tcflush(3), tcsendbreak(3)

Files: termios(4)